The Therapeutic Effects of Dietary Supplements on OCD: A Narrative Review

INTRODUCTION: Sufficient amounts of nutrients have been considered important in the pathophysiology of obsessive-compulsive disorder (OCD). In recent years, many studies have examined alleviating symptoms of neurological and behavioral disorders through nutritional change. Thus, we aim to synthesize current knowledge on serum levels of nutrients and other nutraceuticals and their potential impact on OCD symptoms. METHODS: We conducted a targeted literature search of PubMed, EMBASE, and Scopus, including clinical investigations and relevant animal research in June 2025, without applying any publication date restrictions. Articles were selected based on their focus on nutrient interventions and reported OCD-related outcomes. RESULTS: We reviewed evidence on nutritional and neurochemical factors in OCD, including vitamins (B₆, B₉, B₁₂, C, D, and E), mineral supplements (zinc, magnesium, selenium, iron, calcium), glycine, homocysteine, glutamate, N-acetylcysteine, D-cycloserine, omega-3, and inositol, alongside selected pharmacologic neuromodulators including gabapentin, serotonin-targeting agents. DISCUSSION: Notable and relatively consistent differences in homocysteine, glutamate, vitamin B₁₂, and vitamin E, as well as zinc levels, were observed between individuals with OCD and healthy controls, suggesting their potential as biomarkers and therapeutic targets. Preliminary evidence also indicates that supplementation with vitamin C, B₆, B₉, B₁₂, vitamin E, zinc, and N-acetylcysteine may contribute to symptom improvement in OCD. CONCLUSION: Certain nutritional interventions appear to offer safe, well-tolerated adjunctive benefits in OCD treatment, likely through anti-inflammatory and antioxidant pathways. However, because of heterogeneity in study designs, small sample sizes, and variable dosing regimens, further research should determine optimal supplement types, dosages, and treatment durations.